The present invention relates to a quantum computing chip, and more specifically, to separating chip mode frequencies from quantum bit frequencies.
In quantum computing, a quantum bit (qubit) is a quantum oscillator that eventually experiences undesirable perturbations in the oscillation amplitude and phase (T1 and T2 relaxation). Longer coherence times (larger values for T1 and T2) correspond with a longer time to perform quantum operations before the system decoheres. Several factors may contribute to the perturbations in the oscillation and hasten the T1 and T2 relaxation. A circuit comprising the qubits, resonators, and signal ports is formed as a thin film on a substrate. The substrate itself may be one source of decoherence. The substrate, typically formed of an insulating material with a high dielectric constant, may be viewed as a microwave resonator with chip resonant modes (chip modes) that may be close to the qubit frequency such that they couple with the qubit frequency and cause decoherence (which we refer to here as the Purcell effect or Purcell loss).